Scavenged from the Wonderland of Rebirth: Artificial Memorial of Perfection

INverse:
Iris Sepperin was a brilliant, if terrible, girl, who had risen to power and fallen gracelessly at the ripe age of (somewhere between fourteen and twenty).
Having been born as the reincarnation of the legendary mage Rosenkreuz, she had at her disposal the knowledge of such a powerful and selfless individual. What she did NOT inherit was his selfless and kind attitude.
Having grown with such great knowledge, Iris saw the world as her plaything, her toy, her belonging. Growing bored one day, she saw fit to antagonize the holy church of her time. They attempted to retaliate, but she played the innocent target, enraging her father, Count/Graf Michael Sepperin, into having the mage's organization, Rozenkreuz Stilette (RKS), declare war on the world.
And so, this ploy to assauge Iris' boredom mostly went without a hitch. Mostly, for one Spiritia Rosenburg rebelled against RKS in an attempt to stop her friends and allies from committing a horrible mistake. This one-woman rebel managed to defeat and placate each RKS member, infiltrate Castle Sepperin, and make the Count himself doubt himself.
Iris would not have this, so she killed her father and dared Spiritia to conquer her own Golden Palace. This challenge Spiritia did take up on. Many trials later, Spiritia and Iris finally fought amongst the clouds, high above the Golden Palace.
Spiritia... lost. Yet before Iris would move to finish off the interloper with her own power of Blitzstrahl, Ascended Memorized Phantasm manifested at the will of kuni, who had witnessed everything.
The manikin army held Iris off as kuni ascended to the topmost part of AMP. Standing before the faux Door-to-Paradise, he created a Perfect Manikin of Iris to counter and strike down the self-proclaimed 'ruler-goddess' of the world.
Thus Luna Sepperin was born as the equal and opposite to the mad Iris Sepperin.

Luna Sepperin, as a person, is an upbeat, charismatic even, young woman. She also seems to have gained that which Iris lacked: sympathy for her fellow man. Often, when kuni allows for Perfect Manikins to fight, she volunteers to keep the other Perfect Manikins healthy and hale. By the time the 'Anti-Magic's Wish' arc is in full swing, Luna has taken to helping two manikins, a 'Spirit of the Rose-Cross' and a 'Messenger of the Rose-Cross', complete the conversion to Perfect Manikin-hood.

Luna has inherited Iris' personal power of Blitzstrahl (lit. 'Lightning Flash'), a 'Lightning attack worthy of a goddess'. Its power is on par with Killing Lightning, interestingly enough.
While Luna has Iris' looks down pat (young adult, blonde, apparently pettanko/flat-chested), her eyes are of the Midnight Blue color. Though, under specific circumstances (read, goddess/goddess-slaying mode), she gains Iris' red eyes. (I suppose to compensate for the lack of seraph wings that Iris gets in desperate-mode.)

Big spoilers-ish on my internal canon. Even moreso than usual. If you care not, click.

By the end of the 'Anti-Magic's Wish' arc, Luna is forced, along with Tia and Freu (the two Manikins that have by this time attained sentience), to guard part of Everlasting Dream, a temporal anomaly that leads to AMP. When the heroes of the arc enter their part, they are trapped there, with the only way to proceed being the combat-induced death of at least one of the stationed guardians. Luna, unwilling to let her two friends be parted, offers herself as the tribute, though not without effort on the heroes' part.
The wills of Perfect Manikin and creator clash, the resulting symphony revealing how well Luna was suited to defeating those similar to Iris. Lightning arced across the false sunrise-lit sky as Blitzstrahl fell upon the judged in inexhaustable waves. Magics borne of hellish pursuits was recreated in impossible time-frames. All those who witnessed knew that the deadly ballet would be remembered forever.
Yet such an impressive display came to an inevitable end as kuni arose victorious. Struck down by the hand of her creator, Luna accepted her death with the poise and grace of a true goddess. Her only wish was that Tia and Freu be kept safe as the heroes pressed onward to end the dream.
With a peaceful smile that represented true beauty, Luna Sepperin was unmade.

Hey, what's this?:
Luna, in contrast to Iris, is a much more sensible person. Whereas Iris would kill a priest for the hell of it, Luna would kill only the deserving or at her master's request.
Luna is actually kinda-like a goddess in some respects. That is, the kindness of a good-natured goddess, and the fury of a pissed-off goddess.
Manikin designation is 'Goddess of the Rose-Cross'.
(It took me this long to realize that Perfect Manikins share the same initials as Puella Magi. Excuse me while I think of positive things, with the help of this Ladder.)
Luna is just as tech savvy as her original. Let's just say she knows how a pilot a Wily Machine and leave it at that.

Letzte Schlacht!
Erste Stage der Iris ~ Das goldene Schloss / Red Pollusion (stage theme)
Eröffnungsstage ~ Der Anfang vom Ende / The Ground Which Can Shine (1st alternate stage theme)
Freudias Stage ~ Die Konfrontation des Schicksals / Pegasus (2nd alternate stage theme)
Stunde der Entscheidung / The Devil Loves a Fallen Angel (Confrontation)
Thema der Irisbosse / Closed Garden (Luna Machine)
Thema der Irismachinen / Pray to Muse For... (Duel Theme)
Spiritias Thema / Fighting Spirits (1st alternate Duel Theme - Tia)
Freudias Thema / 22 (2nd alternate Duel Theme - Freu)
Einstellungen & Replay / First Love (Farewell)